Emotions influence people in many aspects. This project examines the effect of people’s emotions on their motion, with focus on balance and posture while standing, and walking initiation. In two within-subjects designed experiments we manipulated participants’ emotional state using movies to four varying in valence and arousal:​ happiness, relaxation, sadness, and fear. Motion was measured using motion capture system and force plate.

Experiment 1 explored factors that might play roles in the effect:​ valence and arousal of emotions, gender, and emotional regulation. Results showed lowest balance under fear mainly in sideways movements, and sadness leads to head leaning most downward and under relaxation most upward and upright. There is also a slower first step gained from fear state, compared to positive emotions. Analysis of gender differences reveals men had lower balance during standing under sadness and fear, and women under happiness and fear. Greater gender differences were in the effect of sadness on balance during standing in forward-backward direction, with men exhibiting lower balance and women exhibiting higher balance and larger first step. In addition, under relaxation state men demonstrate most upright head position;​ under fear women produce slowest initiation of step. Participants’ tendency to engage in cognitive reappraisal as emotion regulation is associated with lower balance under relaxation state. Relying on regulatory focus theories, we compared emotions associated with prevention (relaxation and fear) and emotions associated with promotion (happiness and sadness). Results show that relaxation and fear have different effects on balance and head position during standing;​ happiness and sadness show differences in forward-backward balance and head position.

Experiment 2 focused on the role of regulatory focus. Participants were selected based on a measure of their chronic regulatory focus. Results reveal promotion-focused participants felt stronger happiness than prevention-focused. Regulatory focus mechanisms decrease balance under fear and positive emotion associated with each, i.e., relaxation effect prevention-focused and happiness effect promotion-focused;​ promotion-focused demonstrate stronger effects on balance between happiness and sadness, and effects on head position. Emotions have stronger effect on prevention-focused balance in forward-backward direction and on promotion-focused balance in sideways direction. For both, sadness led to higher balance. Also, prevention-focused had fewer changes in shoulders positions compare to relaxation;​ under relaxation they used smallest range of motion in the slowest manner and made slower first step compare to negative emotions. First step was faster under high arousal emotion associated with each of the regulatory focus mechanisms, i.e., promotion-focused under happiness and prevention-focused under fear.

In both experiments emotions affect balance mainly in sideways motion, where negative emotions differ the most;​ highest balance gained under sadness and lowest under fear. Position of the head is affected mostly by low arousal states, where head leans most downward under sadness and most upward under relaxation. Women (vs. men) act more consistently.

This research can contribute to development of emotion recognition model. Further research is needed on a large variety of ages and cultures.